package huawei_nowcoder;

import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

/**
 * @order  10
 * @decription 字符个数统计
 */
public class CharNumberStatistics {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        String str=scanner.nextLine();
        char[] chars=str.toCharArray();

        Set set=new TreeSet() ;
        for (char i:chars
        ) {
            set.add(i);
        }
        System.out.println(set.size());
    }
}
